In various systems, load sensors are used to detect and quantify a mechanical load. For example, in an aircraft braking system, load sensors may be used to measure a mechanical load. The term mechanical load may generally refer to force, but may also refer to pressure. Of course, as pressure comprises a force distributed over an area, either pressure or force may be determined for a known area of measurement. Accordingly, mechanical load may refer to force, pressure, or both.
Conventional load sensors typically comprise one or more resistance elements that are glued or otherwise affixed to an elastic body such as a steel member. A force generator (such as an actuator) generates force which compresses the steel member, which deforms the resistance element, and thus, changes the electrical resistance of the resistance element. The resistance change may then be interpreted as a load change.
Such sensors must be produced with great care, and often at greater cost, so that the accuracy of the sensor is maintained over a variety of environmental conditions, such as changes in temperature. Further, such sensors typically do not measure load accurately when the load is not applied directly in line with the resistance element.
In addition, conventional sensors have size limitations. Typically, conventional sensors comprise an annular disk and have a diameter to thickness ratio of about three to one. This ratio may be disadvantageous in many applications using a relatively thin sensor, and in applications where excess weight is disfavored, such as in an aircraft. When a load sensor is used with an actuator, longer and/or thicker sensors are generally disfavored as well.
There is a need for a less costly load sensor that supports accurate readings, even where force is not applied uniformly across the sensor. Accordingly, there is a need for a load sensor having an improved diameter to thickness ratio.